A battery of 20 cells (each having e.m.f. 1.8V and internal resistance `0.1Omega` is charged by 220 volts and the charging current is 15A. Calculate the resistance to be put in the circuit.

Options

A. 4m/s
B. `10m/s^2`
C. `5m/s2`
D. `2sqrt2m/s^2`

Answer

(D)

Explanation

`a=("Net force on system")/("total mass of system")=(5g-mu(5g))/(5+5)=(50(1-0.2))/10=4m/s^2 a_cm=|(m_1veca_1+m_2veca_2)/(m_1+m_2)|=a/sqrt2=2sqrt2m//s`